1. Field of the Invention
The present invention relates to an audio system for a vehicle having a plurality of speaker units which cooperatively generate sound for a vehicle passenger compartment.
2. Background Art
Audio systems are provided in vehicle passenger compartments to generate sound for passengers. Some audio systems include a pair of speaker units positioned relative to a front-driver position and a front-passenger position in the vehicle passenger compartment.
It is desirable that the audio signals heard by passengers in either position be balanced as if the passenger was positioned equidistant from each speaker. The proper balancing of the audio signals is referred to as a stereo image. A balanced stereo image allows a person in either position to hear sound which appears to be originating equally from the front-driver side and front-passenger side speaker units.
Many vehicle audio systems produce an unbalanced stereo image. An unbalanced stereo image causes the passenger to perceive sound generated by the audio system to be localized to one side of the vehicle. Typically, this was a result of the differential positioning of the speaker units relative to passenger position in the vehicle.
For example, the front-driver side speaker unit is positioned much closer to the front-driver position than the front-passenger position. As such, the audio sounds originating from the front-driver side speaker unit will arrive at the front-driver position prior to the audio sounds originating from the front-passenger speaker unit.
The unbalancing of the stereo image causes the driver to hear more sound from the front-driver speaker unit than the front-passenger speaker unit due to differential timing or magnitude of the sounds received from each speaker.
The unbalanced sound, which is commonly referred to as near-side localization, is a problem that disrupts stereo imaging at both the front-driver and passenger positions. Accordingly, there exists a need to provide an audio system for a vehicle which provides a balanced stereo image to both the front-driver and passenger positions.